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Biomedical subjects

K H Reid

Publications and source records attributed to K H Reid.

54 records · Page 3Linked to original sources
PubMed1985

The acute periventricular injury syndrome: a possible animal model for psychotic disease.

A new experimental brain syndrome involving localized periventricular damage induced by intracerebroventricular injections of lysophosphatidyl choline has been developed in adult rats. The acute periventricular injury syndrome is characterized by transient weight loss, decreased emotionality, extreme postural indifference (catalepsy), inappropriate aggressive responses, impaired grooming, cerebral ventricular enlargement, and periventricular damage to both cells and fiber sheaths. This syndrome appears to simulate several features of schizophrenia, and it may prove useful in the study of psychotic disorders in man.

Acute Disease↗
PubMed1985

A dual chamber for comparative studies using the brain slice preparation.

A dual linear-flow chamber for comparative studies using brain slices is described. Electrophysiological and ultrastructural analysis of rat hippocampal slices incubated in the chamber showed that its two compartments allows performance of reliable paired comparison studies in a highly efficient manner.

Anaerobiosis↗
PubMed1984

Resistance to hypoxia in the rat hippocampal slice.

Rat hippocampal slices showed marked local variations in sensitivity to hypoxia within the CA1 region, judged by electrical criteria. There were also marked differences between slices, judged both by electrical and histological criteria. Local differences were attenuated by 'adapting' slices for 3-4 h in a uniformly oxygenated bath before testing. The local differences may reflect proximity to capillaries.

Animals↗
PubMed1984

The stability of the hippocampal slice preparation: an electrophysiological and ultrastructural analysis.

The viability and stability of the in vitro rat hippocampal slice preparation were assessed using electrophysiological and electron microscopical means. Slices exhibited lifetimes of 6-19 h. Correlation between the duration of electrical activity and changes in ultrastructure of these slices was found. Possible reasons for the wide variability in lifetime of the hippocampal slice are suggested.

Animals↗
PubMed1984

Variability of bregma in 300 gram Long-Evans and Sprague-Dawley rats.

Bregma is used as an anatomical reference point for most freehand and some stereotaxic injections into the rat brain. The variability of bregma with respect to the intraaural line has been examined previously for rats of a wide range of weights. We examined this variability in 282-326 gram male rats of the Long-Evans and Sprague-Dawley strains. In both strains, mean bregma was less than that stated in a widely used stereotaxic atlas. Furthermore, the mean bregma of the Sprague-Dawley rats was significantly greater than that for the Long-Evans strain. The results suggest that bregma is inadequate as an anatomical reference for intraventricular injections in rats unless the volume injected is a substantial fraction of ventricular volume.

Animals↗
PubMed1983

Autonomic responses to dental procedures in pedodontic patients during a standard restoration session.

Autonomic and behavioral responses to seven dental procedures were studied in 21 pedodontic patients aged six to 12. When mean pulse rate, pulse amplitude, absolute skin conductance, and skin-conductance responses were compared over all subjects, the injection of the local anesthetic consistently elicited the greatest response. In five patients where anesthesia was inadequate, painful high-speed drilling also elicited large responses. When autonomic responses were compared between high-anxious and low-anxious children, both groups showed similar transient responsiveness. High-anxious children showed a significantly higher basal level of sympathetic activity.

Anesthesia, Dental↗
PubMed1981

Surgical determination of the site of crossing of jaw-opening reflex evoked by tooth pulp stimulation in the cat.

Tooth pulp stimulation in the cat evokes a jaw-opening reflex that is usually bilateral. We defined the location of fibers crossing to activate the contralateral reflex by making midline sagittal transections at peripheral and central levels in 11 anesthesized cats. A local midsagittal transection of the brain stem 2-4 mm above the obex selectively eliminated the contralateral reflex response. Midline sagittal transections of the maxilla, mandible, cervical cord, or upper brain stem did not.

Afferent Pathways↗
PubMed1979

The CASE system for cancer education.

A Computer-Assisted-Self-Evaluation (CASE) program in oncology is described. The program is based on motivation by immediate, informative feedback, and involves the computer-guided interaction of a student with a series of microfiche cards. The computer leads the student through a series of 16 questions and associated explanations and recommendations based on the answer choices. Since all textual materials are placed on microfiche cards, the computer is only required to print simple, prearranged sentences and comments. As a result four students, using different CASE topics, can time-share the same computer terminal. This time-sharing capability, together with the large but compact, low cost information storage afforded by the use of microfiche, makes the cost of this system comparable to that of conventional study aids. The use of the CASE system as an educational aid and self-tutoring mechanism has been well accepted by faculty and students.

Attitude↗
PubMedDate not supplied

Comparative effect of flunarizine in two animal models of stroke.

1. A common 'stroke model', the rat middle cerebral artery occlusion preparation, was used to compare photocoagulation with mechanical occlusion. 2. Areas of cerebral infarction and of vascular leakage were compared using these two methods. The general pattern of damage was similar, with central infarcted areas surrounded by larger vascular leakage areas. 3. The two models differed in the extent of their vascular leakage areas and in their response to the cerebroprotective agent flunarizine. 4. We conclude that the two models are not equivalent, probably because they do not damage the vascular endothelium to the same degree.

Animals↗
PubMedDate not supplied

Responses of rat hippocampal slices in a high-K+ medium following in vivo global ischaemia.

1. We hypothesized that burst activity induced in rat hippocampal tissue by a high-K+ medium in vitro would be increased by a previous episode of global ischaemia, severe enough to induce persistent neurological dysfunction. 2. Male Wistar rats that were subjected to 9 min of chest compression, sufficient to reduce blood pressure (BP) to zero, showed evidence of neurological damage attributed to a global ischaemic insult. Hindlimb function was impaired for 24-48 h and a susceptibility to sound-induced seizures was induced in 25 to 35 rats. The seizure susceptibility cleared spontaneously within 2 weeks in 10 of 25 rats. 3. Hippocampal slices from postischaemic rats were prepared, tested for viability and were then exposed to an 8.0 mmol/L K+ artificial cerebrospinal fluid in vitro. Spontaneous epileptiform bursting activity in the high-K+ medium was not increased. Instead, burst size decreased with time after ischaemia. 4. The decrement in bursting activity is attributed to loss of cellular activity or integrity. These changes correlate with functional changes described by others, but not necessarily to histologically verifiable cell death. The time course of these changes was remarkably long, continuing for almost 3 weeks. Thus, a less-than-lethal ischaemia appears to induce neuronal changes, possibly reversible, that continue for at least 20 days after the global ischaemic insult.

Animals↗
PubMedDate not supplied

Impedance of amalgam-dentin interface in cat tooth.

The impedance between two amalgam electrodes implanted in the maxillary canine of a cat was measured at various frequencies between 0.02 kilohertz (kHz) and 100 kHz. When plotted on the X-R plane as a function of frequency, two types of impedance loci were obtained. One resembled a circular are at low frequencies, whereas the other was parabolic or exponential in formmthe circular-arc loci are similar to those calculated from membrane models. The parabolic or exponential loci are predicted by a polyelectrolyte model.

Animals↗